Process for preparing isobutene cyclopentadiene-methylcyclopentadiene terpolymers

ABSTRACT

The present invention relates to a process for preparing isobutene-cyclodiene copolymers having a number-average molecular weight of at least 100,000 and an unsaturation of 1˜30% by mol, characterized in that polymerization is carried out without gelation by reacting 75˜99.5% by weight of an isobutene and 0.5˜25% by weight of a cyclodiene or a mixture of cyclodiene as reaction materials, in a polar reaction solvent of 1˜10 times by weight with respect to the reaction materials, wherein a catalyst solution of 0.02˜2% by weight in the polar solvent is used in the amount of 0.2˜2 times by weight with respect to the reaction materials, at a reaction temperature of -100°˜-85° C., thereby obtaining a copolymer, and then removing the residual catalyst activity at a temperature of -100°˜-25° C.

TECHNICAL FIELD

The present invention relates to a process for preparingisobutene-cyclodiene copolymers. More particularly, the presentinvention relates to a process for preparing isobutene-cyclodienecopolymers having a number-average molecular weight of at least 100,000and a degree of unsaturation of 1˜30% by mol, characterized in thatpolymerization is carried out by reacting isobutene with conjugatedcyclic compounds such as cyclopentadiene, methylcyclopentadiene,cyclohexadiene, methylcyclohexadiene, methylenecyclohexene, etc.; orwith unconjugated cyclic compounds such as pinene, etc.; or with amixture thereof, without gel formation even under the reaction conditionof high content of cyclodiene.

BACKGROUND ART

Heretofore, the process for producing isobutene-cyclodiene copolymershas been well known. In order to appreciate the commercial utility ofthe copolymer as a rubber, the copolymer should possess appropriatemechanical strength and strong adhesive strength as well as a highnumber-average molecular weight and a high degree of unsaturation.

It is known that as the number-average molecular weight of the copolymerincreases, the copolymer's tensile strength tends to increase, and asthe number of unsaturation bond of the copolymer increases, thecopolymer's adhesive strength with respect to another rubber tends toincrease. In other words, when the copolymer is vulcanized together withhighly unsaturated rubber such as natural rubber etc., the adhesivestrength of the copolymer increases as the number of unsaturation bondincreases and the crosslinking reaction increases and the similarity incrosslinking behavior will also increase.

Isobutene-isoprene copolymer ("butyl rubber") is well known as arepresentative example of existing isobutene-diene copolymer. But butylrubber has less than 2.5 mol % of isoprene content as comonomer, whichhas double bond; thus, it has low number of crosslinking sites which canbond with other rubber. Also its crosslinking reaction behavior isdifferent from the highly unsaturated rubber. All of the above forexample, results in its weak adhesive strength which decreases furtherwhen exposed to external shock, vibration etc. As a method of improvingadhesive strength of butyl rubber, it has been proposed to incorporatehalogen compounds into butyl rubber, such as chorine and bromine whichcan promote the crosslinking reaction, and to increase isoprene content.But in case of the former, investment on additional equipment isrequired for halogenation process of the resulting polymer after theproduction of the polymer. In case of the latter, although improvedadhesive strength is obtained, there exists the problem of decreasinggas barrier property, which is one of the most desirable properties ofbutyl rubber. Moreover, U.S. Pat. Nos. 3,356,661, 3,165,503 and3,466,268 etc. reported that the higher the content of isoprene, thelower the number-average molecular weight and as a result, the copolymerof little utility value is produced. Also it is known that the structureand quantity of the unsaturated bond influence the resistance of rubberagainst aging. In case of butyl rubber, the degree of unsaturation islower than that of natural rubber, so it is somewhat stable againstaging, but because the site of unsaturation is in the polymer backbone,this polymer is subject to ozone cleavage, thus the aging of rubbercannot be avoided.

On the other hand, in case of isobutene-cyclodiene copolymer which issimilar to butyl rubber, improvement in adhesive strength is obtained aswell as excellent gas barrier property even at high degree ofunsaturation. Even if the unsaturation bond is attacked and cyclicstructure is severed, the copolymer backbone will be highly resistant toozone attack because the diene compound having cyclic structure iscopolymerized and the unsaturation bond does not exist on the backbone.Thus the resistance of rubber against aging is excellent and itsimproved characteristics makes it an excellent tire material. Eventhough the above-mentioned isobutene-cyclodiene copolymer solved theproblem associated with existing butyl rubber and are consideredexcellent material for tires, the copolymer faces another problem inthat it is difficult to maintain the comonomer in high purity becausethe comonomer is unstable against heat. Also as the degree ofunsaturation increases, the gel formation increases and the molecularweight decreases. These problems in preparation have prevented saidpolymer from being producted for commercial use.

Among processes for preparing isobutene-cyclopentadiene copolymer of theprior slurry polymerization methods, U.S. Pat. No. 2,356,128 producedonly copolymers of low molecular weight. U.S. Pat. No. 2,577,822disclosed a process for preparing terpolymer having high molecularweight which used a divinylbenzene to give crosslinking. U.S. Pat. No.3,080,337 disclosed a process for preparingisobutene-cyclopentadiene-isoprene terpolymer without gelation and U.S.Pat. No. 3,239,495 disclosed a process for preparing terpolymer of highmolecular weight using divinylbenzene.

However, these slurry processes produce a polymer of low molecularweight due to cyclopentadiene dimer (DCPD) and water which were includedin their reaction materials, or a polymer of poor physical propertieswhich cannot be used as a commercial product due to the addition ofdivinylbenzene which increased the crosslinking of the polymer produced.

Although isobutene-cyclopentadiene copolymers having a useful degree ofunsaturation and molecular weight can be produced by effectivelyremoving water and dicyclopentadiene from the reaction materials,problems such as gelation and fouling were experienced as the degree ofunsaturation and molecular weight of the copolymer increased.Particularly, in a slurry batch polymerization process, it wasimpossible to produce a polymer having a homogeneous degree ofunsaturation because in the initial stage of the polymerizationreaction, when cyclopentadiene having a high reaction rate was used, apolymer having a high degree of unsaturation was obtained and gelationwas observed.

By conducting a slurry continuous polymerization together with theremoval of impurities which would decrease the molecular weight ofcopolymer, isobutene-cyclopentadiene copolymer without gelation can beproduced. However, it was difficult to prevent reactor fouling in aslurry continuous reaction. The technique to extend continuous operationtime by preventing fouling is an important index to measure theeconomical performance of a slurry process.

The problem with gel formation and molecular weight decrease can besolved by the well known solution process, however, it is impossible toobtain high conversion because the viscosity of the reactants increasessharply when the polymerization proceed. Also, in order to obtain highmolecular weight of the polymer, the production cost together with theinvestment cost will increase since the temperature has to be maintainedat a level of -120° C.

A number of examples of process for producing isobutene-cyclodienecopolymers by solution process are shown below:

In U.S. Pat. No. 3,808,177, an isobutene-cydopentadiene copolymer havinga number-average molecular weight of at least 120,000 and a degree ofunsaturation of 8˜30 mol % at no more than 10% of conversion, wasprepared by carrying out a polymerization reaction using aluminiumchloride dissolved in methyl chloride as catalyst and aliphaticsaturated hydrocarbon with 5˜10 carbon atoms as reaction solvent atpolymerization temperature of -120° C.

In U.S. Pat. No. 3,856,763, an isobutene-cyclopentadiene copolymerhaving a number-average molecular weight of at least 120,000 and adegree of unsaturation of 8˜40 mol % at no more than 10% of conversion,was prepared using the chioro or bromo allyl aluminium dihalide withalkyl groups of 1˜4 carbon atoms as catalyst at polymerizationtemperature of -120° C.

In U.S. Pat. No. 4,031,360, an isobutene-cyclopentadiene copolymerhaving a number-average molecular weight of at least 90,000 and a degreeof unsaturation of 8˜35 mol % at no more than 10% of conversion, wasprepared by carrying out a solution polymerization method usingaluminium halide or alkyl aluminium dihalide as catalyst atpolymerization temperature of -120° C.

In U.S. Pat. No. 4,139,695, an isobutene-methylcyclopentadiene copolymerhaving a number-average molecular weight of at least 120,000 and adegree of unsaturation of 8˜30 mol % at no more than 5% of conversion,was prepared using alkyl aluminium dichloride as catalyst andmethylcyclohexane as reaction solvent at polymerization temperature of-120° C.

Even though an isobutene-cyclodiene copolymer, including cyclopentadieneof which the number-average molecular weight and the degree ofunsaturation are high and gel content is low, can be prepared by thesolution process, this solution process has several problems as shownbelow.

In solution process, since the produced copolymer is dissolved in thereaction solvent, the viscosity of the solution increases rapidly as thereaction proceeds, so that the homogeneous mixing of the solution isimpossible, and a large amount of power is used for stirring thesolution. Also, since the viscosity of the solution increases, itbecomes difficult for the solution which serves as a medium for removingreaction heat to transfer the heat to refrigerant and to control thereaction temperature. In particular, a temperature gradient inside thereactor occurs by local temperature increases, so that it is difficultto prepare polymers having homogeneous physical property. Therefore,there is a high risk of producing low quality products.

For preparing polymers having a number-average molecular weight of atleast 100,000, the increase of viscosity becomes a bigger problem sincethe polymerization must be carried out at a extremely low temperature of-120° C. compared to that of slurry process. Further, in order tomaintain the low temperature, very large cooling capacity is required,and the amount of refrigerant used must be increased, resulting in anincrease of the production cost.

Also, to keep the solution in homogeneous phase at lower polymerizationtemperature, the required amount of reaction solvent becomes larger;however, the problem of producing lower molecular weight polymersbecomes more severe with the increase of the amount of solvent used.

Therefore, in order to overcome the above mentioned problems, theconversion of reaction must be kept as low as 10%. However, in thiscase, due to the rapid increase of amounts of reactant and solvent whichare recycled, the distillation unit and moisture purification unit wouldhave to be enlarged, resulting in increase of the production cost.Further, when conversion of reaction is maintained at a low level, thereis a burden to separate and recycle the comonomer since cyclopentadienedoes not completely react at low conversion. And, since the reactionsolvent is not readily volatilized, high temperature is required fordegassing the residual solvent, impairing the double bond in theproduced isobutene-cyclodiene copolymer and deteriorating thecopolymer's physical property.

DISCLOSURE OF INVENTION

It is the object of the present invention to provide a process forpreparing isobutene-cyclodiene copolymers having a high degree ofunsaturation and a high molecular weight, without gelation, by slurryprocess which overcomes the problems of known solution process, saidslurry process being more efficient and economical.

Another object of the invention is to provide a process for preparingisobutene-cyclodiene terpolymers which has an improved vulcanizationreactivity by introducing a second cyclodiene comonomer.

In order to achieve these objects, the present invention provides aprocess for preparing copolymer and terpolymer more efficiently andeconomically by a slurry process, in which the copolymer and terpolymerare prepared using isobutene as a main monomer, and cyclodiene comonomersuch as cyclopentadiene, methylcyclopentadiene, methylcyclohexadiene andthe like, by itself or in mixtures, without gelation, by slurrypolymerization at a temperature from -100° to -85° C. The resultingproduct possesses remarkably improved adhesive strength, ozoneresistance and mechanical properties as compared to the priorbromo-butyl rubber. According to the present invention, high molecularweight isobutene-cyclodiene copolymer having a high conversion rate isprepared by the polymerization reaction of isobutene andcyclopentadiene, methylcyclopentadiene orcyclopentadiene-methylcyclopentadiene mixture. More particularly, thepresent invention provides a process for preparing ofisobutene-cyclodiene copolymers having a number-average molecular weightof at least 100,000 and a degree of unsaturation of 1˜30% by mol, saidprocess is characterized in that it is carried out by a polymerizationreaction without gelation at a polymerization temperature of -100°C.˜-85° C., using 75˜99.5% by weight of isobutene and 0.5˜25% by weightof a cyclodiene or a mixture of cyclodiene as the reaction materials,and the polar solvent of 1˜10 times by weight with respect to thereaction materials as reaction solvent, and using a catalyst solution of0.02˜2% by weight in the polar solvent and the amount of catalystsolution being 0.2˜2 times by weight with respect to the reactionmaterial; then removing the residual catalyst activity from the producedpolymer at low temperature to obtain isobutene-cyclodiene copolymershaving a number-average molecular weight of at least 100,000 and adegree of unsaturation of 1˜30% by mol.

The comonomers which are suitable for the invention includes aconjugated diene having a 5-membered ring structure, such ascyclopentadiene, 1-methylcyclopentadiene, 2-methylcyclopentadiene,1,3-dimethylcyclopentadiene and the like; a conjugated diene having a6-membered ring structure, such as 1,3-cyclohexadiene,1-methyl-1,3-cyclohexadiene, 1-methylene-2-cyclohexene,2-methyl-1,3-cyclohexadiene, 1,3-dimethyl-1,3-cyclohexadiene and thelike; a bicyclic compound containing an unsaturated bond, such aspinene, etc or the mixture thereof.

The isobutene-cyclodiene copolymer in which said comonomer isintroduced, has high vulcanization performance even at low degree ofunsaturation. Thus, it overcomes problems such as deterioration ofmolecular weight, gelation, and reduction of catalyst efficiency, whichare generated when the degree of unsaturation is increased for improvingadhesive strength and vulcanization performance in prior art. In themean time, said copolymer displays a stability of the slurry. Further,at low degree of unsaturation, glass transition temperatures (Tg) ofsaid copolymer is low, and it is possible to prepare higher molecularweight copolymer, which leads to the improved mechanical property ofcopolymer.

In U.S. Pat. Nos. 3,808,377, 4,031,300 and 4,139,695, which alsodisclose the process of preparation of isobutene-cyclodiene copolymers,attempts were made to improve the properties of the copolymers byintroducing diene or cyclodiene comonomers, but due to characteristicsof solution polymerization, the resulted copolymer have either aconversions ratio of as low as 10% or the copolymers obtained have lowmolecular weights even at a very low temperature of less than -100° C.

Hereinafter, the invention is explained in detail.

Materials used for polymerization in the present invention areisobutene, methylcyclopentadiene and cyclopentadiene, with theirrespective purities of more than 99%, 97% and 95%; the composition ratioof reaction materials is 75 to 99.5% by weight of isobutene, 0.5 to 25%by weight, preferably 1 to 20% by weight of comonomer.

Because of the thermal unstability and very high reactivity ofcyclopentadiene and methylcyclopentadiene, they are spontaneouslydimerized into dimers at room temperature. The polymerization conductedin the presence of these dimers in the comonomers, results in molecularweight decrease by blocking chain growth and promotion in gel formationduring polymerization. Thus, the introduction of these dimers into thepolymerization reaction should be prevented if possible, particularly inthe case of high composition ratio of comonomers.

Further, if dicyclopentadiene (the dimers of cyclopentadiene) arepresented in large amounts in cyclopentadiene, they will increase thefreezing point of reaction mixtures due to the dicyclopentadiene's highfreezing point of 33° C. And, at the reaction condition of lowtemperature they will be partially solidified and thus decrease thehomogeneity of polymerization. Accordingly, the dicyclopentadiene arelimited to an amount of 5% by weight, preferably of 2% by weight incyclopentadiene.

As reaction solvents, in order to control the concentration of reactionmaterials and to remove the heat of reaction, the reaction solvents maybe polar solvents, and may be used in an amount from 1- to 10-fold,preferably 2- to 5-fold, by weight with respect to the reactionmaterial. Suitable polar solvents used include alkyl halides having 1 to3 carbons, preferably alkyl chlorides having 1 to 3 carbons, and morepreferably methyl and ethyl chloride.

When the above polar solvents are used as a reaction solvent, polymerproduced during the reaction is not soluble in the solvent and remain ina state of slurry, this will restrain the rapid increases in viscosityof reaction mixtures, so that it is possible to remove effectively thereaction heat. Accordingly, it becomes possible to control temperaturegradient in a reactor. As a result, the processes have the economicadvantages in stirring operation, material transfer, as well as theeasiness in maintaining reaction temperature, allowing reactionconversion to be maintained remarkably high, compared to known solutionprocess of prior art.

As to catalysts, they may be catalysts of Lewis acid type, and includepreferably aluminum halide, alkyl aluminum dihalide, boron halides ormixtures thereof, and more preferably aluminum chloride, methyl aluminumdichloride, ethyl aluminum dichloride, t-butyl aluminum dichloride,boron fluoride, boron chloride or mixtures thereof. Each catalyst may beused in combination with the desired ratios.

To dissolve and incorporate the catalysts, solvents used may be allylhalides having 1 to 3 carbons, preferably alkyl chlorides, and morepreferably methyl and ethyl chloride.

Catalysts are adjusted to the concentrations of 0.02 to 2% by weight,preferably 0.05 to 0.5% by weight, in catalyst solutions, which are usedin amount of 0.2- to 2-fold by weight with respect to reactionmaterials. In cases when catalysts are added in high concentration,local temperature increases due to the heat of vigorous reaction, andthus copolymers of low molecular weights and gels are tend to beproduced. Accordingly, the concentration of catalysts should be keptbelow a certain range.

Water in reaction materials, reaction solvents, or catalyst solutionsare known to lower molecular weights, as well as serving as an inhibitorof catalytic activity, thus it should be removed if possible.Accordingly, water in reaction materials, reaction solvents, or catalystsolutions are maintained in amounts of less than 20 ppm, preferably lessthan 5 ppm, and more preferably 1 ppm.

Reaction temperature is kept in the between -100° to -85° C., preferablybetween -97° to -90° C. Reactants and catalyst solutions are precooledto about the desired reaction temperature in the precooler viaflowmeters, and then added at a constant rate continuously into thereactor of jacket type by fine-tuning valves, and as soon as added intothe reactor, they are vigorously stirred so as to be mixedhomogeneously. Also, the reactor is pre-charged with reaction solventsand then reactant and catalysts are introduced into the reactor. Indoing so, it becomes possible to control the temperature increase due toa radical reaction in the early stage of the reaction, and to preventthe production of copolymers of low molecular weights and gels due tothe the local increases in temperature in the reactor.

Polymers, released continuously from the outlet of the reactor, areterminated by using deactivating agents, and then are recovered afterdrying them in an oven under vacuum. Water and alcohols can be used asthe deactivating agents.

Deactivation of residual catalysts should be conducted at lowtemperature of -100° to -25° C., preferably -90° C. to -50° C., as soonas they are released from the reactor. This is because when thetemperature is elevated, the residual catalysts remain active, andcopolymers of low molecular weights will be produced by cationicpolymerization. Thus deterioration of the properties of the finalproducts may occur. In addition, other type of reactions includinggelation, which occur at a extremely slow rate at low temperature, mayoccur faster as the temperature increases, thus products of whichstructure is different from those of desired polymers may be produced.Therefore, effective deactivation of residual catalysts depends greatlyupon treatment temperature so it is desirable to deactivate the residualcatalyst at low temperature near polymerization temperature, immediatelyas polymers are released from the reactor.

Isobutene-cyclodiene copolymers prepared according to the presentinvention have number-average molecular weights of more than 100,000 andhave unsaturation of 1 to 30% by mol.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention is explained in further detail withreference to Examples. However, it should be understood that thefollowing Examples are intended to illustrate the invention withoutlimiting it in any way.

Herein, "gel" means the insoluble part of used copolymer when thecopolymer is dissolved in the suitable solvent such as hexane, and"conversion" means weight percent of consumed reaction material tointroduced reaction material (isobutene, diene). Further "degree ofunsaturation" means the mol % of diene which included in the producedisobutene-cyclobutadiene copolymer.

EXAMPLE 1

2% by weight of cyclopentadiene which includes 1% by weight ofdicyclopentadiene and 98% by weight of isobutene was copolymerized usingmethyl chloride as reaction solvent which has weight ratio of 75:25 withrespect to reaction material, with 0.1% by weight of catalyst solutionof aluminum chloride dissolved in methyl chloride, weight of solutionwas 1 times with respect to reaction material, at the reactiontemperature of -97° C.

An isobutene-cyclopentadiene copolymer with a number-average molecularweight of 330,000 and a degree of unsaturation of 2.3 mol % wasproduced. The residual catalyst in the resulting copolymer wasdeactivated at -90° C. using methanol, and the copolymer wasprecipitated and then recovered. Gel formation ratio in polymerizationreaction was a trace amount of 0.5 weight % or less.

EXAMPLES 2˜5

An isobutene-cyclopentadiene copolymer was produced in the same manneras in Example 1, except that dicyclopentadiene contents included incyclopentadiene and the quantity of cyclopentadiene in the reactionmaterial were changed as shown in Table 1. In Table 1, the molecularweight and degree of unsaturation of the resultant copolymer are shown.Gel formation ratio was a trace amount of 0.5 weight % or less.

                                      TABLE 1    __________________________________________________________________________         CPD.sup.1 contents                  DCPD.sup.2 contents                          Reaction solvent/                                  Number- Degree of                                                Gel         in the reaction                  in the CPD                          reaction material                                  average molecular                                          unsaturation                                                formation ratio    Example         material (weight %)                  (weight %)                          (weight ratio)                                  weight  (mol %)                                                (weight %)    __________________________________________________________________________    1     2       1       75/25   330,000 2.3   trace.sup.3                                                amount    2             2               327,000 2.2   trace                                                amount    3             5               297,000 2.2   trace                                                amount    4    10       1               177,000 11.0  trace                                                amount    5             2               174,000 10.7  trace                                                amount    __________________________________________________________________________     Note     .sup.1 CPD means cyclopentadiene.     .sup.2 DCPD means dicyclopentadiene.     .sup.3 a trace amount means 0.5 weight % or less.

Comparative Example 1

Isobutene-cyclopentadiene copolymer was produced in the same manner asin Example 1, except that the dicyclopentadiene contents included incyclopentadiene was 10% by weight. Copolymer with 214,000 ofnumber-average molecular weight, 2.2 mol % of unsaturation degree, 1.8weight % of gel formation ratio was obtained. Accordingly, as thedicyclopentadiene contents included in cyclopentadiene increase, thenumber-average molecular weight tends to reduce and at the same time gelformation ratio tends to increase.

EXAMPLES 6˜10

An isobutene-cyclopentadiene copolymer was produced in the same manneras in Example 1, except that the contents of cyclopentadiene in thereaction material and concentration of the catalyst solution werechanged as shown in Table 2.

In Table 2, molecular weight and unsaturation degree of the resultantcopolymer are shown. Gel formation ratio was a trace amount of 0.5weight % or less.

                                      TABLE 2    __________________________________________________________________________         CPD contents                  Reaction solvent/                          Catalyst solution                                  Number  Degree of                                                Gel         in the reaction                  reaction material                          concentration                                  average molecular                                          unsaturation                                                formation ratio    Example         material (weight %)                  (weight ratio)                          (weight %)                                  weight  (mol %)                                                (weight %)    __________________________________________________________________________    6     2       75/25   0.3     314,000 2.3   trace                                                amount    7                     1.0     260,000 2.2   trace                                                amount    8    10       75/25   0.3     154,000 10.8  trace                                                amount    9                     1.0     134,000 10.4  trace                                                amount    10   20       75/25   0.3     108,000 21.5  trace                                                amount    __________________________________________________________________________

Comparative Examples 2 and 3

An isobutene-cyclopentadiene copolymer was produced in the same manneras in Examples 6 and 8, except that the respective concentration ofcatalyst solution was 3.0% by weight. Molecular weight, degree ofunsaturation, and gel formation ratio are shown in Table 3. Comparedwith the results of Table 2, we can see that as the concentration ofcatalyst solution increases the number-average molecular weight tends toreduce and also gel formation ratio tends to increase.

                                      TABLE 3    __________________________________________________________________________          CPD contents                   Reaction solvent/                           Catalyst solution                                   Number  Degree of                                                 Gel    Comparative          in the reaction                   reaction material                           concentration                                   average molecular                                           unsaturation                                                 formation ratio    Example          material (weight %)                   (weight ratio)                           (weight %)                                   weight  (mol %)                                                 (weight %)    __________________________________________________________________________    2      2       75/25   3       217,000 2.2   2.5    3     10       75/25   3        82,000 10.4  7.0    __________________________________________________________________________

Comparative Examples 4˜11

An isobutene-cyclopentadiene copolymer was produced in the same manneras in Examples 6 to 10, except that the concentration of the catalystsolution was changed as shown in Table 4, and the residual catalyst wasdeactivated at room temperature. Molecular weight, degree ofunsaturation, and gel formation ratio of the resultant copolymer areshown in Table 4. Compared with the Table 2, we can see that the gelformation ratio is considerably higher, and the removal of catalyticactivity should effect quickly at near the low polymerizationtemperature.

                                      TABLE 4    __________________________________________________________________________          CPD contents                   Reaction solvent/                           Catalyst solution                                   Number  Degree of                                                 Gel    Comparative          in the reaction                   reaction material                           concentration                                   average molecular                                           unsaturation                                                 formation ratio    Example          material (weight %)                   (weight ratio)                           (weight %)                                   weight  (mol %)                                                 (weight %)    __________________________________________________________________________    4     2        75/25   0.3     298,000 2.2   0.8    5                      1.0     212,000 2.2   1.9    6                      3.0     185,000 2.3   3.7    7     10       75,25   0.3     127,000 11.0  1.6    8                      1.0      96,000 10.5  3.2    9                      3.0      66,000 10.7  16.0    10    10        75,25  0.3     84,000  21.6  2.3    11                     1.0      57,000 21.8  6.8    __________________________________________________________________________

EXAMPLES 11˜15

An isobutene-cyclopentadiene copolymer was produced in the same manneras Example 1, except that the content of cyclopentadiene of the reactionmaterial was changed as shown in Table 5. Molecular weight and degree ofunsaturation of the resultant copolymer are shown in Table 5, gelformation ratio being 0.5 weight % or less.

                                      TABLE 5    __________________________________________________________________________         CPD contents                  Reaction solvent/                          Catalyst solution                                  Polymerization                                         Number   Degree of         in the reaction                  reaction material                          concentration                                  Temp.  Average Molecular                                                  unsaturation    Example         material (weight %)                  (weight ratio)                          (weight %)                                  (°C.)                                         weight   (mol %)    __________________________________________________________________________    11   1        75/25   0.1     -97    482,000  1.0    12   2                               327,000  2.3    13   5                               240,000  5.2    14   10                              174,000  10.4    15   20                              132,000  24.7    __________________________________________________________________________

EXAMPLES 16˜20

An isobutene-cyclopentadiene copolymer was produced in the same manneras Example 11˜15, except that the reaction temperature was changed to-92° C. Molecular weight and degree of unsaturation of the resultantcopolymer are shown in Table 6, gel formation ratio being 0.5 weight %or less.

                                      TABLE 6    __________________________________________________________________________         CPD contents                  Reaction solvent/                          Catalyst solution                                  Polymerization                                         Number   Degree of         in the reaction                  reaction material                          concentration                                  Temp.  Average Molecular                                                  unsaturation    Example         material (weight %)                  (weight ratio)                          (weight %)                                  (°C.)                                         weight   (mol %)    __________________________________________________________________________    16   1        75/25   0.1     -92    298,000  1.0    17   2                               210,000  2.3    18   5                               177,000  5.3    19   10                              129,000  10.4    20   20                              103,000  23.5    __________________________________________________________________________

EXAMPLES 21˜23

An isobutene-cyclopentadiene copolymer was produced in the same manneras Example 11, 13 & 14, except that ethyl chloride was used as areaction solvent. Molecular weight and unsaturation level of theresultant copolymer are shown in Table 7, gel formation ratio being 0.5weight % or less.

                                      TABLE 7    __________________________________________________________________________         CPD contents                  Reaction solvent/                          Catalyst solution                                  Polymerization                                         Number   Degree of         in the reaction                  reaction material                          concentration                                  Temp.  Average Molecular                                                  unsaturation    Example         material (weight %)                  (weight ratio)                          (weight %)                                  (°C.)                                         weight   (mol %)    __________________________________________________________________________    21   1        75/25   0.1     -97    430,000  1.0    22   5                               244,000  5.1    23   10                              165,000  10.8    __________________________________________________________________________

EXAMPLES 24˜26

An isobutene-cyclopentadiene copolymer was produced in the same manneras Examples 11, 13 & 14, except that ethyl aluminium chloride was usedas a catalyst.

Molecular weight and unsaturation level of the resultant copolymer areshown in Table 8, gel formation ratio being 0.5 weight % or less.

                                      TABLE 8    __________________________________________________________________________         CPD contents                  Reaction solvent/                          Catalyst solution                                  Polymerization                                         Number   Degree of         in the reaction                  reaction material                          concentration                                  Temp.  Average Molecular                                                  unsaturation    Example         material (weight %)                  (weight ratio)                          (weight %)                                  (°C.)                                         weight   (mol %)    __________________________________________________________________________    24   1        75/25   0.1     -97    444,000  1.0    25   5                               237,000  5.2    26   10                              179,000  10.3    __________________________________________________________________________

EXAMPLES 27˜29

An isobutene-cyclopentadiene copolymer was produced in the same manneras Example 11, 13 & 14, except that boron fluoride was used as acatalyst. Molecular weight and unsaturation level of the resultantcopolymer are shown in Table 9, gel formation ratio being 0.5 weight %or less.

                                      TABLE 9    __________________________________________________________________________         CPD contents                  Reaction solvent/                          Catalyst solution                                  Polymerization                                         Number   Degree of         in the reaction                  reaction material                          concentration                                  Temp.  Average Molecular                                                  unsaturation    Example         material (weight %)                  (weight ratio)                          (weight %)                                  (°C.)                                         weight   (mol %)    __________________________________________________________________________    27   1        75/25   0.1     -97    501,000  1.0    28   5        242,000 5.3    29   10       169,000 10.6    __________________________________________________________________________

EXAMPLES 30˜32

An isobutene-cyclopentadiene copolymer was produced in the same manneras Example 4, except that the ratio of reaction solvent to the reactionmaterial was changed as shown in Table 10. Molecular weight andunsaturation level of the resultant copolymer are shown in Table 10, gelformation ratio being 0.5 weight % or less.

                                      TABLE 10    __________________________________________________________________________         CPD contents                  Reaction solvent/                          Catalyst solution                                  Polymerization                                         Number   Degree of         in the reaction                  reaction material                          concentration                                  Temp.  Average Molecular                                                  unsaturation    Example         material (weight %)                  (weight ratio)                          (weight %)                                  (°C.)                                         weight   (mol %)    __________________________________________________________________________    30   10       50/50   0.1     -97    168,000  10.7    31            75/25                  174,000  10.7    32            85/15                  172,000  10.2    __________________________________________________________________________

EXAMPLES 33˜35

An isobutene-cyclopentadiene copolymer was produced in the same manneras Example 4 except that the catalyst solution concentration was changedas shown in Table 11. Molecular weight and unsaturation degree of theresultant copolymer are shown in Table 11, gel formation ratio being 0.5weight % or less.

                                      TABLE 11    __________________________________________________________________________         CPD contents                  Reaction solvent/                          Catalyst solution                                  Polymerization                                         Number   Degree of         in the reaction                  reaction material                          concentration                                  Temp.  Average Molecular                                                  unsaturation    Example         material (weight %)                  (weight ratio)                          (weight %)                                  (°C.)                                         weight   (mol %)    __________________________________________________________________________    33   10       75/25   0.05    -97    170,000  10.3    34                    0.1            171,000  10.4    35                    0.3            154,000  10.4    __________________________________________________________________________

EXAMPLES 36˜41

An isobutene-cyclodiene copolymer was produced by performingpolymerization reaction at the temperature of -97° C., using 0.1% byweight of catalyst solution of aluminum chloride dissolved inmethylchloride, the weight of solution being 1 times with respect to thereaction material, using methylcyclopentadiene and cyclopentadiene ascomonomer and methylchloride as the reaction solvent which is 3 times byweight with respect to the reaction material thereof. The residualcatalyst in the resulting copolymer was deactivated at -80° C. usingmethanol, and the copolymer was precipitated and then recovered.

                                      TABLE 12    __________________________________________________________________________         MCPD.sup.4 contents                  CPD contents                           Reaction solvent/                                   Catalyst solution                                           Number   Degree of         in the reaction                  in the reaction                           reaction material                                   concentration                                           Average Molecular                                                    unsaturation    Example         material (weight %)                  material (weight %)                           (weight ratio)                                   (weight %)                                           weight   (mol %)    __________________________________________________________________________    36   2        --       75/25   0.1     294,000  2.3    37            3                        221,000  5.5    38            5                        182,000  7.5    39   5        --                       216,000  5.7    40            3                        169,000  8.9    41            5                        140,000  11.3    __________________________________________________________________________     Note.     .sup.4 MCPD means methylcydopentadiene.

EXAMPLES 42˜45

An isobutene-cyclodiene copolymer was produced in the same manner asExamples 37, 38, 40 and 41, except that the reaction temperature was-92° C.

                                      TABLE 13    __________________________________________________________________________         MCPD contents                  CPD contents                           Reaction solvent/                                   Catalyst solution                                           Number   Degree of         in the reaction                  in the reaction                           reaction material                                   concentration                                           Average Molecular                                                    unsaturation    Example         material (weight %)                  material (weight %)                           (weight ratio)                                   (weight %)                                           weight   (mol %)    __________________________________________________________________________    42   2        3        75/25   0.1     173,000  5.4    43   2        5                        147,000  7.5    44   5        3                        136,000  9.1    45   5        5                        121,000  11.4    __________________________________________________________________________

EXAMPLE 46

An isobutene-cyclodiene copolymer was produced in the same manner asExample 37 except that the reaction solvent was ethylchloride, and theresultant polymer had a number-average molecular weight of 205,000 and adegree of unsaturation of 5.5 mol. %.

EXAMPLE 47

An isobutene-cyclodiene copolymer was produced in the same manner asExample 37 except that the weight ratio of reaction solvent/eactionmaterial was 85/15, and the resultant polymer has a number-averagemolecular weight of 220,000 and a degree of unsaturation of 5.5 mol. %.

EXAMPLE 48

An isobutene-cyclodiene copolymer was produced in the same manner asExample 37 except that the concentration of catalyst solution was 0.3%by weight, and the resultant polymer had a number-average molecularweight of 208,000 and a degree of unsaturation of 5.6 mol. %.

EXAMPLES 49˜51

An Isobutene-cyclopentadiene copolymer was produced in the same manneras Example 37 except that catalyst was changed as shown in Table 14.

                                      TABLE 14    __________________________________________________________________________         CPD contents                  MCPD contents                           Reaction solvent/                                   Catalyst/                                           Number   Degree of         in the reaction                  in the reaction                           reaction material                                   catalyst                                           Average Molecular                                                    unsaturation    Example         material (weight %)                  material (weight %)                           (weight ratio)                                   solution                                           weight   (mol %)    __________________________________________________________________________    49   3        2        75/25   Aluminum                                           203,000  5.6                                   bromide                                   /methyl chloride    50                             Boron fluoride.                                           217,000  5.5                                   isobutanol/                                   methyl chloride    51                             Ethyl aluminum                                           208,000  5.7                                   dichloride/methyl                                   chloride    __________________________________________________________________________

As shown in the Table above, isobutene-cyclodiene copolymers having anumber-average molecular weight not less than 100,000, an unsaturationdegree of 1˜30% by mol and a gel formation ratio of 0.5% by weight orless can be produced without gel formation according to the presentinvention by performing polymerization reaction at the temperature of-100°˜85° C., using aluminium halide, alkyl aluminium dihalide and boronhalide as catalyst and polar solvent of 1˜10 times by weight withrespect to the reaction material as reaction solvent; said reactionsolvent serves to control the concentration of reactant and to removethe reaction heat in order to prevent dissolution of the resultantpolymer. The residual catalyst activity in polymer effluent is instantlydeactivated after polymerization is carried out by reacting isobutenewith cyclopentadiene or methylcyclopentadiene.

We claim:
 1. A process for preparingisobutene-cyclopentadiene-methylcyclopentadiene terpolymers having ahigh number-average molecular weight by reacting isobutene,cyclopentadiene and methylcyclopentadiene at low temperature, whereinthe isobutene-cyclopentadiene-methylcyclopentadiene terpolymers have anumber-average molecular weight of at least 100,000 and an unsaturationof 3 to 20 percent by mol,characterized in that a continuous slurrypolymerization is carried out without gelation and fouling by reacting85 to 98 percent by weight of isobutene and 2 to 15 percent by weight ofa mixture of cyclopentadiene and methylcyclopentadiene as reactionmaterials, in a polar reaction solvent of alkylhalide of 1 to 10 timesby weight with respect to the reaction materials, wherein a catalystsolution of 0.02 to 2 percent by weight is used in the amount of 0.2 to2 times by weight with respect to the reaction materials, at a reactiontemperature of -100° to -85° C. to produce a terpolymer, the catalyst insaid catalyst solution being deactivated at a temperature of -100° to-25° C., wherein dimer content in the cyclopentadiene and themethylcyclopentadiene is at most 2 percent by weight, and water contentin the reaction materials, the reaction solvents or the catalystsolutions are maintained in amounts of less than 20 ppm.
 2. A processfor preparing isobutene-cyclopentadiene-methylcyclopentadieneterpolymers according to claim 1, characterized in that the reactiontemperature is -97° to -90° C.
 3. A process for preparingisobutene-cyclopentadiene-methylcyclopentadiene terpolymers according toclaim 1 characterized in that the residual catalyst activity is removedat the temperature of -90° to -50° C.
 4. A process for preparingisobutene-cyclopentadiene-methylcyclopentadiene terpolymers according toclaim 1 characterized in that an alkyl halide containing 1 to 3 carbonatom(s) is used as the reaction solvent.
 5. A process for preparingisobutene-cyclopentadiene-methylcyclopentadiene terpolymers according toclaim 4 characterized in that methylchloride or ethylchloride is used asthe reaction solvent.
 6. A process for preparingisobutene-cyclopentadiene-methylcyclopentadiene terpolymers according toclaim 4 or 5 characterized in that the reaction solvent is used in theamount of 2 to 5 times by weight of the reaction materials.
 7. A processfor preparing isobutene-cyclopentadiene-methylcyclopentadieneterpolymers according to claim 1 characterized in that aluminium halide,alkyl aluminum dihalide, boron halide, or a mixture thereof is used asthe catalyst.
 8. A process for preparingisobutene-cyclopentadiene-methylcyclopentadiene terpolymers according toclaim 7 characterized in that aluminum chloride, aluminum bromide, ethylalulminum dichloride, boron fluoride, or a mixture thereof is used asthe catalyst.
 9. A process for preparingisobutene-cyclopentadiene-methylcyclopentadiene terpolymers according toclaim 7 or 8 characterized in that the concentration of the catalyst ina catalyst solution is 0.05 to 0.5% by weight.